A Coupled Energy-Water Storage Architecture for Resilient Urban Power and Water Distribution

This white paper proposes a coupled energy-water storage architecture to enhance the resilience of urban power and water distribution networks. The concept leverages GLIDES concept (Ground-Level Integrated Diverse Energy Storage), which is a pneumo-hydraulic storage technology developed at Oak Ridge National Laboratory, to enable mechanically coupled, long-duration, and bidirectional energy exchange between electric and water infrastructures. By integrating high-pressure hydraulic storage with municipal water distribution systems through a controllable hydraulic transformer, the proposed approach enables co-optimization of electricity and water operations and providing cross-sector resilience during grid disturbances or water supply disruptions.

Energy and water are foundational pillars of urban infrastructure and essential for public health and community resilience. However, urban energy and water systems are increasingly strained by rising demand, aging infrastructure, and the growing impacts of extreme weather and grid disturbances. Many cities experience high peak electricity costs and vulnerability to cascading outages, where disruptions in one network will rapidly affect the distribution in another network.

Based on GLIDES concept, we propose the energy-water storage architecture coupled with the municipal water distribution system, see Figure 3 in the whitepaper. In charging mode, electricity from grid/renewables drives the water pump station to pump water inside the storage vessel with pressurization from hydraulic transformer. When power or water demand peaks, the compressed air pushes water back through the turbine to regenerate electricity to the grid or maintaining water network pressure. This storage stores energy as water pressure and compressed air, so it can prevents service interruptions and help both electricity and water system recover faster during outages.

In urban settings where electric and water infrastructures are co-located, the proposed coupled energy-water storage architecture enables new synergies:
1. Enable dual-use infrastructure by coupling with existing tanks, reservoirs, or water distribution system to co-store water and energy, reducing redundant capital costs.
2. Stabilize renewable-powered desalination and treatment by maintaining near-constant pressure and flow for reverse osmosis and filtration processes, thereby reducing specific energy consumption (kWh/m3) and membrane wear.
3. Shift pumping and distribution loads by absorbing surplus renewable power during low water demand and releasing hydraulic energy during peak hours to flatten grid and pressure fluctuations.
4. Provide safe, long-duration backup for water utilities by offering resilience during outages without fire or chemical risks associated with batteries.
The near-term opportunity lies in designing and demonstrating a pilot-scale GLIDES system integrated with a municipal or industrial water facility (e.g., desalination, water reuse, or pumping station) to evaluate multi-domain efficiency, load flexibility, and resilience performance.

Success of a near-term GLIDES-water integration pilot can be assessed using quantitative and qualitative metrics:
- Energy-Water Co-Optimization: Reduction peak grid load and stabilization of pressure/flow within optimal reverse osmosis operating range.
- Operational Efficiency: Reduction of specific energy consumption for desalination or water treatment.
- Resilience and Reliability: Sustained operation of critical water services for longer hours during grid disruptions.